1. Field of the Invention
This invention relates, in general, to hydraulic couplings, and specifically to hydraulic couplings used in undersea drilling and production applications. More particularly, the invention involves a pressure balanced hydraulic coupling wherein radial passages are positioned to allow connection or disconnection of the coupling without substantial fluid pressure exerted axially against the face of the male member. Further, the invention relates to a pressure balanced coupling with a split body to facilitate insertion and removal of one or more radial seals.
2. Description of Related Art
Subsea hydraulic couplings are old in the art. The couplings generally consist of a male and female member with sealed fluid passageways connecting therebetween. The female member generally is a cylindrical body with a relatively large diameter longitudinal bore at one end and a relatively small diameter longitudinal bore at the other. The small bore facilitates connections to hydraulic lines, while the large bore seals and slidingly engages the male member of the coupling. The male member includes a cylindrical portion at one end having an outer diameter approximately equal to the diameter of the large bore in the female member of the coupling. The male member also includes a connection at its other end to facilitate connection to hydraulic lines. When the cylindrical portion of the male member is inserted into the large bore of the female member, according to various embodiments of the device, fluid flow is established between the male and female members.
Problems arise with the use of hydraulic couplings in relatively high pressure systems due to the high axial forces imposed on the male and female members during the coupling operation and during their use. In such couplings, it is necessary for the fluid force opposing the face of the male or female member to be overcome before the fluid communication is established between the members. In a relatively high pressure system, high forces imposed on the valve members may render the connection of the coupling members difficult. Also, during use, fluid pressure is exerted between the male and female members in such a way as to tend to separate them. The force necessary to join the members and the resultant tendency of the coupling members to separate are characteristic problems in the prior art. High pressure systems and undersea applications also experience problems associated with sealing the junction between the male and female members.
Ideally, hydraulic couplings should, as far as possible, be pressure balanced, so that fluid pressure does not hinder connection or urge separation of the members. The coupling members often include valves that open automatically on coupling and close automatically on uncoupling. The coupling also should prevent implosion of seals due to a vacuum when the coupling members are separated. Finally, to prevent loss of fluid in coupling or uncoupling, the coupling should employ seals which can withstand high pressures as well as the corrosive effects of undersea or other adverse environments.
The insertion and removal of radial seals from the bore of the female member also can present difficulties, when one or more seals are retained in the female member. With the use of undersea hydraulic couplings at greater ocean depths, deterioration or buildup of silt and/or other debris can degrade the seal and necessitate its replacement. The present invention is intended to provide an undersea hydraulic coupling that solves all of these needs and requirements.
Undersea hydraulic couplings are disclosed in the prior art. In U.S. Pat. Nos. 4,694,859 and 5,762,106 to Robert E. Smith, III, undersea hydraulic couplings with radial metal seals are shown. The radial metal seal is retained on a shoulder in the female bore. The seal is pressure energized to seal radially with the circumference of the male member and with the female member bore. In U.S. Pat. No. 4,754,780, to Robert E. Smith, III, a pressure balanced hydraulic coupling is shown having radial passages communicating between the male and female members so that hydraulic fluid flow is in a substantially radial direction and is not exerted against the face of either member. U.S. Pat. No. 4,832,080 to Robert E. Smith, III, discloses a pressure balanced hydraulic coupling with metal seals used to seal the annulus between the male and female members when they are coupled. The metal seals may be pressure energized in response to fluid pressure in the coupling to enhance the sealing effect. U.S. Pat. Nos. 4,900,071 and 5,052,439 to Robert E. Smith, III disclose undersea hydraulic couplings with two-piece retainers including a cylindrical retainer sleeve member slidably received within the female member bore, and a threaded retainer locking member threaded to the wall of the central bore. An elastometric seal is restrained from radial movement by a dovetail interfit with a mating shoulder on the retainer sleeve and/or the retainer locking member. U.S. Pat. No. 5,099,882 to Robert E. Smith, III discloses a pressure balanced hydraulic coupling having radial passages in the male and female members, a first pair of radial seals positioned on each side of the radial passages for sealing between the receiving chamber and the seal retainer, and a second pair of radial seals positioned on each side of the radial passage for sealing between the seal retainer and the male member. The seals are pressure energized metal seals. U.S. Pat. No. 5,232,021 to Robert E. Smith, III discloses a probe member for an undersea hydraulic coupling having at least one circumferential depression in its outer cylindrical body, for disengaging one or more radial seals during the insertion or withdrawal of the probe member from the receiving chamber of the female member. U.S. Pat. No. 5,277,255 to Robert E. Smith, III discloses an undersea hydraulic coupling with pressure energized seals. The seals are configured to seal radially between the male and female members of the coupling so that hydraulic fluid does not leak from the annular space between the receiving chamber and outer surface of the male member. U.S. Pat. No. 5,360,035 to Robert E. Smith, III discloses a poppet valve that is pressure balanced for use in an undersea hydraulic coupling. When the poppet valve is open, radial passages are interconnected through an annular cavity between the poppet valve body and the valve bore.